JP2010092945A - Adhesive film for semiconductor wafer protection and method of protecting semiconductor wafer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive film for semiconductor wafer protection that prevents a semiconductor wafer from being broken even when the semiconductor wafer is made into a thin layer and has superior operability such as tape cuttability, and to provide a method of protecting semiconductor wafer using the film. <P>SOLUTION: The adhesive film includes a resin layer A containing a copolymer of 4-methyl-1-pentene and 5-8C α-olefin other than 4-methyl-1-pentene, the copolymer having a fusion point Tm of 110 to 240°C measured by a differential scanning type calorimeter and containing 1 to 60% by mol of the 5-8C α-olefin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adhesive film for protecting a semiconductor wafer, and a semiconductor wafer surface protecting method using the film.

  Conventionally, in the die bonding process, a method in which a resin paste, which is a die bonding material, is supplied onto a lead frame, and a semiconductor chip is mounted thereon and bonded is most often used.

  However, when the resin paste is used, it is difficult to apply the resin paste uniformly on the lead frame, so that voids may occur when the adhesive layer is cured, and chip cracks may occur.

  For the purpose of improving the non-uniform coating property, which is a defect of the resin paste that is a die bonding material, and rationalizing the overall process, Patent Document 1 discloses a method that uses an adhesive film for die bonding in the die bonding process. It is disclosed.

  This method includes a step of adhering an adhesive film for die bonding to a circuit non-formation surface of a semiconductor wafer, a dicing step of dividing and cutting the semiconductor wafer in a state of adhering the adhesive film for die bonding to a dicing tape, And a step of die bonding the semiconductor chip to the lead frame after the step of peeling the dicing tape.

  However, in this method, when the non-circuit-formed surface of the semiconductor wafer is processed for higher integration and the semiconductor wafer is further thinned, the adhesive film for die bonding is not attached to the adhesive film for protecting the semiconductor wafer. When sticking, a serious problem such as breakage of a semiconductor wafer due to pressure of a roll or the like occurs.

  In addition, when the adhesive film for die bonding is attached with the adhesive film for protecting the semiconductor wafer attached, the adhesive film for protecting the semiconductor wafer is deformed and thinned by the heating performed when the adhesive film for die bonding is applied. There was a problem of damaging.

  In order to solve such problems, Patent Document 2 discloses a wafer protection method using an adhesive film for protecting a semiconductor wafer having a layer formed of a resin having a melting point of 200 ° C. or higher.

However, there has been a demand for a pressure-sensitive adhesive film for protecting a semiconductor wafer that can further prevent damage to the wafer even when the tape is cut and the productivity is high and the wafer is further thinned.
JP-A-6-302629 Patent 3594581

 An object of the present invention is to provide an adhesive film for protecting a semiconductor wafer that prevents damage to the semiconductor wafer and is excellent in workability such as tape cutability, even when the semiconductor wafer is thinned in view of the above problems. Another object of the present invention is to provide a method for protecting a semiconductor wafer using the film.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by improving a base film used for a semiconductor wafer protective film, and have completed the present invention.

That is, the said subject is solved by the semiconductor wafer protection film of this invention, and the semiconductor wafer protection method using the said film.
[1] (1) A melting point measured by a differential scanning calorimeter, which is a copolymer of 4-methyl-1-pentene and an α-olefin having 5 to 8 carbon atoms other than 4-methyl-1-pentene A resin layer A comprising a copolymer having [Tm] in a range of 110 to 240 ° C. and a content of the α-olefin having 5 to 8 carbon atoms in a range of 1 to 60 mol%. Including an adhesive film for protecting semiconductor wafers.
[2] The resin layer A further includes (2) a polymer of 4-methyl-1-pentene, and / or (3) at least one α-olefin selected from α-olefins having 2 to 4 carbon atoms. [1] An adhesive film for protecting a semiconductor wafer, comprising a resin layer A comprising an olefin polymer.
[3] The adhesive film for protecting a semiconductor wafer according to [1], wherein the content of the α-olefin having 5 to 8 carbon atoms in the resin layer A is in the range of 5 to 55 mol%.
[4] The adhesive film for protecting a semiconductor wafer according to [1], including a base film layer composed of the resin layer A and a resin layer B having a melting point of 60 ° C. or higher.
[5] The adhesive film for protecting a semiconductor wafer according to [4], wherein in the base film layer, the thickness of the resin layer A is 10% or more of the thickness of the base film layer.
[6] The adhesive film for protecting a semiconductor wafer according to [5], wherein the resin layer B comprises at least one selected from polyethylene, ethylene-vinyl acetate copolymer, and polypropylene.
[7] A method for protecting a semiconductor wafer using the adhesive film for protecting a semiconductor wafer according to [1] to [6], wherein the adhesive film for protecting a semiconductor wafer is disposed on the circuit forming surface of the semiconductor wafer via the adhesive layer. A first step of attaching the film, a second step of cutting in a circle along the outer periphery of the wafer to which the film is attached, and a third step of processing and thinning the circuit non-formation surface of the semiconductor wafer A fourth step of adhering the adhesive film for die bonding to the circuit non-forming surface of the semiconductor wafer without peeling off the adhesive film for protecting the semiconductor wafer, and a fifth step of peeling off the adhesive film for protecting the semiconductor wafer. And a method for protecting a semiconductor wafer.
[8] The semiconductor wafer protection method according to [7], wherein the second step is grinding, polishing, chemical etching, dry etching, plasma treatment, one of the above steps, or a combination of a plurality of the above steps.

  An adhesive film for protecting a semiconductor wafer that prevents damage to the semiconductor wafer and is excellent in workability such as tape cutability, and a semiconductor wafer protection method using the film, even when the semiconductor wafer is thinned provide.

Hereinafter, the present invention will be described in detail.
1. Semiconductor wafer protecting adhesive film The semiconductor wafer protecting adhesive film according to the present invention is produced by forming an adhesive layer on one surface of a substrate film.

Usually, in order to protect an adhesive layer, a peeling film is stuck on the surface of an adhesive layer.
In consideration of sticking to the surface of the semiconductor wafer through the surface of the adhesive layer exposed when the release film is peeled off, in order to prevent contamination of the semiconductor wafer surface by the adhesive layer, on one side of the release film A method is preferred in which a pressure-sensitive adhesive coating solution is applied and dried to form a pressure-sensitive adhesive layer, and then the resulting pressure-sensitive adhesive layer is transferred to one side of a substrate film.

  The adhesive film for protecting a semiconductor wafer according to the present invention is a copolymer of 4-methyl-1-pentene and an α-olefin having 5 to 8 carbon atoms other than 4-methyl-1-pentene, and is a differential scanning type. A resin layer A containing a copolymer having a melting point [Tm] measured by a calorimeter in a range of 110 to 240 ° C. is included.

  Examples of α-olefins having 5 to 8 carbon atoms that form copolymer (1) with 4-methyl-1-pentene include 1-pentene, 1-hexene, 1-heptene, 1-octene and the like. Among these α-olefins, 1-hexene is particularly preferable because it has a good balance of heat resistance and flexibility.

  The copolymer (1) can be synthesized by using a general polymerization method, for example, by the method described in JP-A-2008-144155.

  The copolymer (1) has a melting point [Tm] (hereinafter sometimes abbreviated as DSC melting point) measured by a differential scanning calorimeter in the range of 110 to 240 ° C, preferably 145 to 215 ° C. Is in range. By having a DSC melting point, the copolymer (1) can prevent the back surface of the adhesive film for surface protection from sticking to the sticking table by heating in the sticking step of the adhesive film for die bonding described later. Here, the DSC melting point [Tm] is determined as the maximum endothermic peak when measured from −50 to 250 ° C. at a temperature rising temperature of 10 ° C./min.

  Further, the resin layer A comprising the copolymer (1) according to the present invention is further (2) a polymer of 4-methyl-1-pentene, and / or (3) α- having 2 to 4 carbon atoms. It can contain at least one polymer of α-olefin selected from olefins.

  Various polymers can be used as the 4-methyl-1-pentene polymer of the polymer (2), but typical commercial products are manufactured by Mitsui Chemicals, Inc., trade name: TPX (registered trademark), product number. : MX-002.

  Moreover, it does not specifically limit as a polymer of the at least 1 or more types of alpha olefin chosen from C2-C4 alpha olefin which forms the said polymer (3), However, Polypropylene and polybutene are mentioned. Representative commercial products include Mitsui Chemicals, Inc., trade name: BURON (registered trademark).

  The mixing method and melting method of the copolymer (1) and the polymer (2) or / and the polymer (3) are not particularly limited. For example, plastmill, Banbury, kneader, roll, single-screw or twin-screw extruder It can carry out using kneading apparatuses, such as.

  Moreover, the content rate of the said C5-C8 alpha olefin in the resin layer A of this invention is the range of 1-60 mol%, Preferably it is the range of 5-55 mol%, More preferably, it is 5-5. It is in the range of 50 mol%. When the content of α-olefin having 5 to 8 carbon atoms is larger than 60 mol%, the heat resistance and mechanical properties of the resin layer A are lowered, and for surface protection in the bonding process of the adhesive film for die bonding. The back surface of the adhesive film sticks to the sticking table, the semiconductor wafer is easily damaged, and the tackiness is also deteriorated. On the other hand, when the content of the α-olefin having 5 to 8 carbon atoms is smaller than 1 mol%, the flexibility of the copolymer is lowered, and the cut property tends to be lowered.

  Here, the content of the α-olefin having 5 to 8 carbon atoms contained in the resin layer A is such that the resin layer A is a copolymer (1), that is, 4-methyl-1-pentene and 4-methyl-1- In the case of a copolymer with an α-olefin having 5 to 8 carbon atoms other than pentene, the copolymer composition (mol%) of the α-olefin having 5 to 8 carbon atoms is used.

  The resin layer A is a copolymer (1), and (2) a polymer of 4-methyl-1-pentene, and / or (3) at least one selected from α-olefins having 2 to 4 carbon atoms When the α-olefin polymer is included, the α-olefin content (mol%) is calculated by the following formula 1.

Α-Olefin content in resin layer A (mol%) = r1 × w1 / (w1 + w2 + w3)
... Formula 1
r1: Content of α-olefin in the copolymer (1) (unit: mol%)
w1: Weight composition of copolymer (1) in resin layer A (unit:% by weight)
w2: weight composition of 4-methyl-1-pentene polymer (2) in resin layer A
(Unit:% by weight)
w3: Weight composition (unit:% by weight) of a polymer of at least one α-olefin selected from α-olefins having 2 to 4 carbon atoms in the resin layer A
However, w1 + w2 + w3 = 100

  The resin layer A may be laminated with a resin layer B made of a resin other than the resin layer A to form a base film.

  Since the resin layer B requires heat resistance in the bonding process of the die-bonding adhesive film, the melting point is preferably 60 ° C. or higher. From the viewpoint of moldability, affinity with the resin layer A, and the like, polyethylene, ethylene -It is preferable to consist of at least 1 sort (s) chosen from a vinyl acetate copolymer and a polypropylene.

  In addition, in the base film composed of the resin layer A and the resin layer B, in order to exhibit the heat resistance, cut property, and flexibility of the resin layer A in a well-balanced manner, the thickness of the resin layer A is the above-mentioned base layer. The thickness is preferably 10% or more of the thickness of the material film layer.

  The base film of the adhesive film for surface protection may be a laminate with another film as long as at least one layer includes the resin layer A. When all the layers do not contain the resin layer A, in the step of attaching the adhesive film for die bonding, the semiconductor wafer is likely to be damaged when the adhesive film for protecting the wafer is thermally deformed or peeled off. Or the cutting property tends to be remarkably lowered.

  Moreover, in the said laminated body, when the adhesive layer is formed in one surface, the direction which has the base film layer containing the said resin layer A in the surface in which the adhesive layer is not formed prevents damage to a semiconductor wafer. It is preferable from the viewpoint. This is because of the excellent flexibility and heat resistance of the 4-methyl-1-pentene random copolymer, the pressure-sensitive adhesive layer is not formed in the wafer back surface processing step or the bonding step of the adhesive film for die bonding. This is presumed to be because it absorbs uneven parts such as chucks that come into contact with the surface.

  In addition to the base film, a resin layer formed from a resin having a low elastic modulus may be laminated for the purpose of improving the protection performance when grinding the back surface of the semiconductor wafer. These resin layers include ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer (alkyl group having 1 to 4 carbon atoms), low-density polyethylene, ethylene-α-olefin copolymer (α-olefin carbon). Examples of the resin film formed from the formulas 3 to 8). Among these, an ethylene-vinyl acetate copolymer film having a vinyl acetate unit content of about 5 to 50% by weight is preferred.

 As a production method of the base film, among those produced by known techniques such as a calendar method, a T-die extrusion method, an inflation method, a casting method, etc., considering the productivity, the thickness accuracy of the obtained film, etc. You can choose.

  When these resins are formed into a film, stabilizers, lubricants, antioxidants, pigments, antiblocking agents, plasticizers, tackifiers, softeners, etc. may be added as necessary. . When various additives such as a stabilizer are added at the time of molding the base film, the additive may move to the pressure-sensitive adhesive layer to change the characteristics of the pressure-sensitive adhesive or contaminate the wafer surface. In such a case, it is preferable to provide a barrier layer between the base film and the pressure-sensitive adhesive layer. Moreover, in order to raise the adhesive force of a base film and an adhesive layer, it is preferable to give a corona discharge process or a chemical process etc. to the one surface of a base film.

  When the base film consists of a plurality of resin layers, it is formed by an extrusion method using a multilayer film forming machine, or another resin formed by an extrusion method on a resin film that has been formed in advance. A method of dry laminating a film is mentioned. In this case, in order to increase the adhesive force between the resin film that has been formed in advance and another resin film, a new adhesive layer is provided between them, or the surface of the resin film is subjected to corona discharge treatment, etc. It is preferable to perform easy adhesion treatment. Moreover, in order to raise the adhesive force of a base film and an adhesive layer, it is preferable to give a corona discharge process or a chemical process etc. to the surface which provides the adhesive layer of a base film.

  The thickness of the entire base film is preferably 50 to 350 μm. Moreover, when laminating a heat resistant film and a low elastic modulus film, the thickness of the former layer is preferably about 10 to 300 μm, and the thickness of the latter layer is preferably about 20 to 300 μm. More preferably, the former thickness is about 15 to 200 μm. Due to its flexibility, the low elastic modulus film layer absorbs uneven steps formed by circuits on the surface of the semiconductor wafer, and has an effect of preventing breakage due to back grinding of the semiconductor wafer.

  The base film layer forming the pressure-sensitive adhesive layer may be either the heat-resistant film side or the low elastic modulus film side.

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film for protecting a semiconductor wafer according to the present invention is not particularly limited as long as it functions sufficiently as a pressure-sensitive adhesive even under the temperature condition when the adhesive film for die bonding is attached. And acrylic adhesives such as natural rubber, synthetic rubber, silicone rubber, acrylic acid alkyl ester, and methacrylic acid alkyl ester. Among these pressure-sensitive adhesives, an acrylic pressure-sensitive adhesive is preferable in consideration of control of physical properties of the pressure-sensitive adhesive, reproducibility, and the like. Further, for example, any one of an adhesive having an adhesive force switching function such as a radiation curing type, a thermosetting type, and a heating foaming type, and a normal adhesive not having a switching function can be used in the present invention.

  Hereinafter, among the adhesives having an adhesive force switching function, an acrylic ultraviolet curable adhesive will be exemplified.

  Specifically, it has 100 parts by weight of an acrylate copolymer having a photopolymerizable carbon-carbon double bond introduced in the molecule, and two or more photopolymerizable carbon-carbon double bonds in the molecule. A pressure-sensitive adhesive containing 0.1 to 20 parts by weight of a low molecular weight compound and 5 to 15 parts by weight of a photoinitiator, and obtained by crosslinking the acrylate copolymer with a crosslinking agent as necessary may be used. it can.

  The acrylic ester copolymer in which a photopolymerizable carbon-carbon double bond is introduced in the molecule is specifically a mixture of a monomer having an ethylenic double bond and a copolymerizable monomer having a functional group, The copolymer is reacted with a monomer containing a photopolymerizable carbon-carbon double bond having a group capable of reacting with a functional group such as a carboxyl group, a hydroxyl group, or a glycidyl group contained in the copolymer.

  Examples of the monomer having an ethylenic double bond include acrylic acid alkyl ester monomers such as methyl methacrylate, -2-ethylhexyl acrylate, butyl acrylate, and ethyl acrylate, and alkyl methacrylate monomers, vinyl such as vinyl acetate. Among the monomers having an ethylenic double bond such as ester, acrylonitrile, acrylamide, styrene, one or more are used.

  Examples of the copolymerizable monomer having the functional group include (meth) acrylic acid, maleic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, and N-methylol (meth) acrylamide. These may be used alone or in combination of two or more.

  The ratio of the monomer having an ethylenic double bond and the copolymerizable monomer having a functional group is preferably 30 to 1% by weight with respect to the former 70 to 99% by weight. More preferably, the latter is 20 to 5% by weight with respect to the former 80 to 95% by weight.

  As a method for introducing a photopolymerizable carbon-carbon double bond into a copolymer of a monomer having an ethylenic double bond and a copolymerizable monomer having a functional group, a carboxyl group present in the copolymer is used. A photoreactive monomer containing a photopolymerizable carbon-carbon double bond having a group capable of reacting with a functional group such as a hydroxyl group or a glycidyl group may be reacted. For example, as a combination of these functional groups, a combination that easily undergoes an addition reaction such as a carboxyl group and an epoxy group, a carboxyl group and an aziridyl group, and a hydroxyl group and an isocyanate group is desirable. In addition, any reaction may be used as long as it is a reaction that can easily introduce a photopolymerizable carbon-carbon double bond, such as a condensation reaction between a carboxylic acid group and a hydroxyl group.

  Low molecular weight compounds having two or more photopolymerizable carbon-carbon double bonds in the molecule include tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetraacrylate, pentaerythritol tetra (Meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. These may use 1 type (s) or 2 or more types. These molecular weights are preferably 10,000 or less. More preferably, it is 5,000 or less.

  Photoinitiators include benzoin, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler ketone, chlorothioxanthone, dodecyl thioxanthone, dimethyl thioxanthone, diethyl thioxanthone, acetophenone diethyl ketal, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy -2-methyl-1-phenylpropan-1-one and the like. These may be used alone or in combination of two or more. The addition amount of the photoinitiator is 5 to 15 parts by weight with respect to 100 parts by weight of the copolymer. Preferably it is 5-10 weight part.

  You may add a crosslinking agent to the said ultraviolet curing adhesive. As a crosslinking agent, epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane -Tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis (1-aziridine) Aziridine compounds such as carboxamide), and isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate and polyisocyanate.

  The ultraviolet curable adhesive can be produced by either solution polymerization in the presence of an organic solvent such as toluene or ethyl acetate, or aqueous emulsion polymerization. In addition, a solvent or water can be added to adjust the concentration or viscosity, or an additive such as a thermal polymerization inhibitor can be added.

  The pressure-sensitive adhesive coating liquid used in the present invention may appropriately contain rosin-based, terpene resin-based tackifiers, various surfactants and the like so as not to affect the object of the present invention in order to adjust the pressure-sensitive adhesive properties. . When the coating solution is an emulsion solution, a film-forming aid such as diethylene glycol monoalkyl ether may be added as appropriate so as not to affect the purpose of the present invention. Moreover, you may adjust to a desired viscosity and solid content with organic solvents, such as ethyl acetate and toluene.

  The thickness of the pressure-sensitive adhesive layer is usually 3 to 100 μm. However, in view of the problem of preventing the intrusion of grinding water by closely adhering to a wafer having a recess or a step on the surface, it is more preferably 10 to 100 μm. preferable.

  In the present invention, when the pressure-sensitive adhesive layer is provided on one surface of the base film, the pressure-sensitive adhesive is used as a solution or an emulsion liquid (hereinafter collectively referred to as a pressure-sensitive adhesive coating liquid), a roll coater, a comma coater. A method of forming an adhesive layer by applying and drying according to a known method such as a die coater, a Mayer bar coater, a reverse roll coater, or a gravure coater can be used. At this time, in order to protect the applied pressure-sensitive adhesive layer from contamination caused by the environment, it is preferable to attach a release film to the surface of the applied pressure-sensitive adhesive layer.

  Alternatively, a pressure-sensitive adhesive coating solution is applied to one surface of the release film according to the above-described known method and dried to form a pressure-sensitive adhesive layer, and then the pressure-sensitive adhesive layer is transferred using a conventional method such as a dry laminating method. A method (hereinafter referred to as a transfer method) may be used.

  Although there is no restriction | limiting in particular in the drying conditions at the time of drying an adhesive, Generally, it is preferable to dry for 10 second-10 minutes in a 80-300 degreeC temperature range. More preferably, it is dried for 15 seconds to 5 minutes in a temperature range of 80 to 200 ° C. In the present invention, in order to sufficiently promote the crosslinking reaction between the crosslinking agent and the pressure-sensitive adhesive polymer, after drying of the pressure-sensitive adhesive coating solution is completed, the pressure-sensitive adhesive film for protecting a semiconductor wafer surface is 5 to 300 at 40 to 80 ° C. You may heat for about hours.

  When manufacturing the adhesive film for protecting a semiconductor wafer of the present invention, from the viewpoint of preventing contamination of the surface of the semiconductor wafer, the production environment of all raw materials such as a base film, a release film, and an adhesive main agent, The preparation, storage, coating and drying environment is preferably maintained at a clean level of class 1,000 or less as defined in US Federal Standard 209b.

The adhesive strength of the surface protective adhesive film of the present invention can be adjusted as appropriate in consideration of the processing conditions of the semiconductor wafer, the diameter of the semiconductor wafer, the thickness of the semiconductor wafer after back grinding, the temperature for attaching the adhesive film for die bonding, and the like.
If the adhesive strength is too low, it will be difficult to attach the surface protective adhesive film to the surface of the semiconductor wafer, the protective performance of the surface protective adhesive film will be insufficient, the semiconductor wafer will be damaged, Contamination due to grinding scraps may occur.

  Also, if the adhesive strength is too high, after performing the backside processing of the semiconductor wafer, when the surface protective adhesive film is peeled off from the semiconductor wafer surface, a peeling trouble may occur with an automatic peeling machine, etc. Or the semiconductor wafer may be damaged. Usually, it is 0.1 to 5 N / 25 mm, preferably 0.1 to 3 N / 25 mm in terms of adhesive strength to the SUS304-BA plate. In the case where the adhesive is an adhesive having an adhesive force switching function such as a radiation curable type, a thermosetting type, or a heated foam type, the adhesive strength after the adhesive force is reduced by switching the adhesive force by radiation irradiation or the like is It is preferable to be within the range.

2. Semiconductor Wafer Protection Method Next, the semiconductor wafer protection method of the present invention will be described in detail.
The method for protecting a semiconductor wafer according to the present invention includes a first step of adhering an adhesive film for protecting a semiconductor wafer to a circuit forming surface of a semiconductor wafer via the adhesive layer, and an outer periphery of the wafer to which the film is adhered. A second step of cutting into a circular shape, a third step of processing and thinning the circuit non-forming surface of the semiconductor wafer, and a circuit non-forming surface of the semiconductor wafer without peeling the adhesive film for protecting the semiconductor wafer The fourth step of attaching the die bonding adhesive film to the substrate and the fifth step of peeling the semiconductor wafer protecting adhesive film are sequentially performed.

  Conventionally, in the back surface processing step, a semiconductor wafer having a thickness of 500 to 1000 μm before grinding is ground and thinned to about 200 to 600 μm depending on the type of semiconductor chip and the like. On the other hand, by applying the protection method of the present invention, it is possible to reduce the thickness until the thickness is 200 μm or less, and to improve the cut property.

  In that case, the minimum thickness of the semiconductor wafer is about 20 μm. When the thickness is reduced to 200 μm or less, a wet etching process or a polishing process can be performed subsequent to the back surface grinding. The thickness of the semiconductor wafer before grinding the back surface is appropriately determined depending on the diameter and type of the semiconductor wafer, and the thickness of the semiconductor wafer after the back surface grinding is appropriately determined depending on the size of the chip to be obtained, the type of circuit, and the like.

  The details of the method for protecting a semiconductor wafer according to the present invention are as follows. First, the release film is peeled from the pressure-sensitive adhesive layer side to expose the surface of the pressure-sensitive adhesive layer, and the surface-protective pressure-sensitive adhesive is applied to the surface of the semiconductor wafer via the pressure-sensitive adhesive layer. A film is attached (first step).

  The operation of adhering the surface protective adhesive film to the surface of the semiconductor wafer may be performed manually, but is generally performed by an apparatus called an automatic attaching machine equipped with a roll-shaped surface protective adhesive film. . As such an automatic pasting machine, for example, Takatori Co., Ltd., model: ATM-1000B, ATM-1100, TEAM-100, Teikoku Seiki Co., Ltd., model: STL series, Nitto Seiki Co., Ltd., Model: DR-8500II, DR-3000II and the like.

As the back surface grinding method, a known grinding method such as a through-feed method or an in-feed method is employed. In either method, back surface grinding is usually performed while supplying water to the semiconductor wafer and the grindstone and cooling.

  Subsequently, it cuts circularly along the outer periphery of the wafer which stuck the said film (2nd process). In this step, if the film has poor cutting properties, burrs are generated, which may hinder uniform polishing in the polishing step described later, and problems such as peeling burrs contaminating the wafer may occur. In addition, the cutter used for cutting is heavily consumed, resulting in a problem that the production efficiency decreases due to the replacement of the cutter.

  A semiconductor wafer is fixed to a chuck table or the like of a back surface processing machine via a base film layer of an adhesive film for surface protection, and the back surface of the semiconductor wafer is processed (third step). In the third process, the backside grinding process, the polishing process, the chemical etching process, the dry etching process, and the plasma processing process of the semiconductor wafer may all be performed, or any one of these processes may be performed. Also good.

  The wet etching process and the polishing process are performed for the purpose of removing strain generated on the back surface of the semiconductor wafer, further thinning the semiconductor wafer, removing an oxide film, etc., pretreatment when forming electrodes on the back surface. The etching solution is appropriately selected according to the above purpose.

  Next, the adhesive film for surface bonding is transported to the bonding step of the adhesive film for die bonding without peeling off the adhesive film for surface protection, and the adhesive film for die bonding is bonded (fourth step). Since the adhesive film for die bonding is stuck without peeling off the adhesive film for surface protection, the semiconductor wafer thinned in the sticking step can be prevented from being damaged. However, in the fourth step, since heating at 50 to 90 ° C. is generally required, it is necessary to prevent the thinned semiconductor wafer from being damaged due to thermal deformation of the surface protective adhesive film. The pressure-sensitive adhesive film for surface protection according to the present invention has a layer containing a 4-methyl-1-pentene random copolymer having a flexible molecular structure, less stress remaining, and less heat flow. It can be suitably used without causing damage to the wafer.

  As an apparatus used at the process of sticking the adhesive film for die bonding, Takatori Co., Ltd. make, ATM: 8200, DM-800, etc. are mentioned, for example. Recently, a so-called inline back surface processing machine has been used in which a back surface processing unit, a die bonding adhesive film attaching unit, and a wafer protecting adhesive film peeling unit are integrated. As such an in-line back surface processing machine, for example, model name: PG300RM manufactured by Tokyo Seimitsu Co., Ltd. may be mentioned.

  Examples of the adhesive film for die bonding include an adhesive film for die bonding in which a varnish made of a mixture of a polyimide resin and a thermosetting resin is applied to the surface of a polyester or polypropylene film to form an adhesive layer. At this time, an additive may be mixed with the mixture of a polyimide resin and a thermosetting resin as needed.

  After the fourth step, the surface protective adhesive film is peeled off (fifth step) and then diced. Although peeling of the adhesive film for surface protection may be performed manually, it is generally performed using an apparatus called an automatic peeling machine. As such an automatic peeling machine, Takatori Co., Ltd., Model: ATRM-2000B, ATRM-2100, Teikoku Seiki Co., Ltd., Model: STP Series, Nitto Seiki Co., Ltd., Model: HR8500-II Etc. Moreover, it is preferable to heat-peel as needed for the purpose of improving peelability. Moreover, after peeling the surface-protective adhesive film as necessary, the semiconductor wafer surface is subjected to treatment such as water washing and plasma washing.

  The surface of the semiconductor wafer after peeling off the surface protective adhesive film is cleaned as necessary. Examples of the cleaning method include wet cleaning such as water cleaning and solvent cleaning, and dry cleaning such as plasma cleaning. In the case of wet cleaning, ultrasonic cleaning may be used in combination. These cleaning methods are appropriately selected depending on the contamination state of the semiconductor wafer surface.

  Semiconductor wafers to which the semiconductor wafer protection method of the present invention can be applied are not limited to silicon wafers, but include wafers of germanium, gallium-arsenic, gallium-phosphorus, gallium-arsenic-aluminum, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples.

In all examples and comparative examples shown below, preparation and application of an adhesive coating solution in an environment maintained at a cleanness of class 1,000 or less as defined in US Federal Standard 209b, backside grinding of a semiconductor silicon wafer, In addition, bonding of an adhesive film for die bonding was performed.

  The present invention is not limited to these examples. Various characteristic values shown in the examples were measured by the following methods.

1-1. Probe tack on the back surface of the adhesive film substrate at 90 ° C. Using “Toyo Seiki Polyken Probe Tack Tester: Model 80-02-01” as a test device, measured in a thermostatic chamber kept at 90 ° C. Went. In this measurement, a probe having a diameter of 5 mm was brought into contact with a square test piece having a side length of 25 mm (back surface of the base film of the adhesive film) at a contact pressure of 1000 g / cm ² for 3 minutes, The probe was peeled off from the test piece at a speed of 10 mm // second, and the force (unit: g / 5 mmφ) required when the probe was peeled off from the test piece was read. For each protective sheet, the test was repeated for five test pieces, and the average value of the probe tack measured for each test piece was adopted as the probe tack at 90 ° C. of the protective sheet.

1-2. Tensile modulus YM (MPa)
Using a Tensilon tensile tester (manufactured by Shimadzu Corporation) in an atmosphere of 23 ° C. and humidity of 50% RH, a tensile rate of 300 mm / Measured in min. The test was repeated 5 times for each base film, and the average value of 5 measurements was adopted.

1-3. Practical evaluation: Tape cutability (tape attachment evaluation)
An automatic pasting machine {manufactured by Nitto Seiki Co., Ltd .; model: DR-3000II} was used. Before starting the evaluation of each adhesive film for protecting a semiconductor wafer, the cutter blade of the tape cutting mechanism of the automatic bonding machine was replaced with a new replacement blade. The adhesive film for protecting a semiconductor wafer obtained in Examples and Comparative Examples was continuously pasted on the surface of 300 silicon mirror wafers (diameter: 200 mm, thickness: about 725 μm) using the automatic pasting machine, The 25th wafer from the 276th sheet to the 300th sheet was observed for tape cutting property. Specifically, the cut surface of the tape attached to the wafer and cut into a circle with a cutter blade along the outer periphery of the wafer is visually observed, and a burr of a size that can be visually recognized (a state in which the tape is not cut smoothly: cut unevenness). ) Was counted for one or more wafers.

1-4: Practical evaluation: Microcrack after grinding (wafer thickness 15 μm)
About each semiconductor wafer protection adhesive film 1-3. No burrs of a visible size were observed from the 25 silicon mirror wafers (diameter: 200 mm, thickness: about 725 μm) attached with the adhesive film for protecting the semiconductor wafer after the tape cut property was observed in FIG. Ten wafers were extracted.

  Grinding the back of the wafer while cooling the silicon mirror wafer with these 5 adhesive films for protecting semiconductor wafers on it with water using a grinding device {manufactured by DISCO Corporation, model: DFG860} The wafer thickness after grinding was set to 15 μm. After the grinding process is finished, for each silicon mirror wafer, the both sides of the front and back surfaces of the wafer are visually observed to check for microcracks (small cracks of about 1 to 2 mm in length). The number of wafers in which was observed was counted.

1-5. Practical evaluation: Damage when picking up a thin wafer after grinding from a heating table Affix the adhesive film for protecting a semiconductor wafer described in Examples and Comparative Examples on the surface of a silicon mirror wafer (diameter: 200 mm, thickness: about 725 μm) After being attached, it was fixed on a chuck table of a fully automatic wafer grinding apparatus (Disco, DFG860) via an adhesive film, and grinding was performed until the thickness of the wafer reached 50 μm.

  The thin wafer thus obtained was adsorbed and fixed on a porous chuck table maintained at a temperature of 90 ° C. via an adhesive film. After holding the suction-fixed state for 2 minutes, the suction of the porous chuck table was released, and the wafer was removed upward from the porous chuck table. When the wafer was removed, the wafer after removal was checked for the presence or absence of cracks or cracks in the wafer that occurred when the back surface of the base material of the adhesive film developed an adhesive force on the porous chuck table. Evaluation was performed on 10 wafers, and the number of wafers having cracks or cracks was counted.

1-6. Α-Olefin Content of Resin Layer A Regarding the α-olefin content of 5 to 8 carbon atoms in the resin layer A, the resin layer A is a copolymer (1), that is, 4-methyl-1-pentene. And a copolymer of an α-olefin having 5 to 8 carbon atoms other than 4-methyl-1-pentene and a copolymer composition (mol%) of the α-olefin having 5 to 8 carbon atoms And

  The resin layer A is a copolymer (1), and (2) a polymer of 4-methyl-1-pentene, and / or (3) at least one selected from α-olefins having 2 to 4 carbon atoms When the α-olefin polymer is included, the α-olefin content (mol%) is calculated by the following formula 1.

Α-Olefin content in resin layer A (mol%) = r1 × w1 / (w1 + w2 + w3)
... Formula 1
r1: Content of α-olefin in the copolymer (1) (unit: mol%)
w1: Weight composition of copolymer (1) in resin layer A (unit:% by weight)
w2: weight composition of 4-methyl-1-pentene polymer (2) in resin layer A
(Unit:% by weight)
w3: Weight composition (unit:% by weight) of a polymer of at least one α-olefin selected from α-olefins having 2 to 4 carbon atoms in the resin layer A
However, w1 + w2 + w3 = 100

2-1. Film formation of the base film Film formation of the base film is performed by using a single-screw single-layer extruder when the film is a single layer, and by a T-die method using a multilayer extruder when the film is a multilayer. Extrusion was performed as follows. For Examples 1 to 9 and Comparative Example 3, the resin described in Table 1 was melt-extruded so as to have the thickness shown in Table 1 under the film forming conditions shown in Table 1, and then a corona treatment machine was applied to the surface in contact with the adhesive. Was used for corona treatment so that the surface tension was 54 dyne / cm or more, and a base film was prepared. However, about the comparative example 1 and the comparative example 2, the base film was created by carrying out the dry lamination of the melt-extruded resin film with the polyethylene naphthalate film and the polyethylene terephthalate film.

2-2. Preparation of adhesive coating solution 48 parts by weight of ethyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of methyl acrylate, 5 parts by weight of glycidyl methacrylate, and 0.5 parts by weight of benzoyl peroxide as a polymerization initiator The mixture was added dropwise to a nitrogen-substituted flask containing 65 parts by weight of toluene and 50 parts by weight of ethyl acetate with stirring at 80 ° C. over 5 hours and further stirred for 5 hours to be reacted. After completion of the reaction, the mixture was cooled, 25 parts by weight of xylene, 2.5 parts by weight of acrylic acid, and 1.5 parts by weight of tetradecylbenzylammonium chloride were added thereto, reacted at 80 ° C. for 10 hours while blowing air, and photopolymerized. An acrylic acid ester copolymer solution into which a carbon-carbon double bond was introduced was obtained. In this solution, 7 parts by weight of benzoin as a photoinitiator and 100 parts by weight of a copolymer (solid content), an isocyanate-based crosslinking agent (trade name: Olester P49-75S, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) 0 parts by weight Dipentaerythritol hexaacrylate (trade name: Aronix M-400, manufactured by Toagosei Co., Ltd.) as a low molecular weight compound having two or more photopolymerizable carbon-carbon double bonds in one molecule A part by weight was added, and a viscosity suitable for coating was prepared with toluene and ethyl acetate to obtain a pressure-sensitive adhesive coating solution.

2-3. Preparation of adhesive film for protecting semiconductor wafer 2-2. The pressure-sensitive adhesive coating solution obtained in 1 was dried on the silicone release treatment surface of a 38 μm thick polyethylene terephthalate film (manufactured by Tosero Co., Ltd .: SP-PET) subjected to silicone release treatment using a comma coater. It was coated and dried so that the thickness of the subsequent pressure-sensitive adhesive layer was 20 μm, and the above-mentioned 2-1. The substrate film obtained in (1) was laminated with the corona-treated surface by dry lamination. After lamination, the substrate was heated at 60 ° C. for 24 hours, and then cooled to room temperature to obtain an adhesive film for protecting a semiconductor wafer.

  Next, preparation of the copolymer A-1, the mixture A-2, and A-3 corresponding to the resin layer A will be specifically described.

[Preparation Example 1] Copolymer A-1
4-methyl-1-pentene and 1-hexene as an α-olefin having 5 to 8 carbon atoms other than 4-methyl-1-pentene were polymerized by the method described in Example 5 of JP-A-2008-144155 4 A random copolymer of -methyl-1-pentene and 1-hexene was used as copolymer A-1. The α-olefin content (copolymerization composition) of 5 to 8 carbon atoms in this copolymer was 45 mol%, and the melting point [Tm] was 165 ° C.

[Preparation Example 2] Mixture A-2
Biaxially, 75% by weight of copolymer A-1 and 25% by weight of 4-methyl-1-pentene resin (manufactured by Mitsui Chemicals, trade name: TPX (registered trademark), product number: MX-002) A mixture A-2 was obtained as a composition melt-kneaded using an extruder. The α-olefin content of 5 to 8 carbon atoms in the mixture A-2 was 33.75 mol%.

[Preparation Example 3] Mixture A-3
Biaxial extrusion of 50% by weight of copolymer A-1 and 50% by weight of 4-methyl-1-pentene resin (manufactured by Mitsui Chemicals, trade name: TPX (registered trademark), product number: MX-002) A mixture A-3 was obtained as a composition melt-kneaded using a machine. The α-olefin content of 5 to 8 carbon atoms in the mixture A-3 was 22.5 mol%.

[Preparation Example 4] Mixture A-4
Composition prepared by melt-kneading 15% by weight of copolymer A-1 and 85% by weight of polybutene resin (manufactured by Mitsui Chemicals, trade name: Bureon (registered trademark)) using a twin screw extruder The product (α-olefin content in the composition: 6.75 mol%) was designated as a mixture A-4.

  The resin layer B-1 used for the resin layer B was low-density polyethylene (manufactured by Mitsui Chemicals, trade name: Mirason (registered trademark), product number: 11P).

[Example 1]
As a base film, the mixture A-2 was formed into a single-layer film having a thickness of 160 μm by forming a film on the film-forming conditions described in Table 1 using a single-screw single-layer extruder. The pressure-sensitive adhesive coating solution prepared according to the above-mentioned method 2-2 was applied according to the above-mentioned method 2-3, thereby obtaining a semiconductor wafer protecting pressure-sensitive adhesive film. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 2]
Except for using as a base film, the mixture A-3 was formed under the film forming conditions described in Table 1 using a single-screw single-layer extruder, and a single-layer film having a thickness of 160 μm was used. In the same manner as in Example 1, an adhesive film for protecting a semiconductor wafer was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 3]
As a base film, the mixture A-2 and the resin B-1 were formed using a multilayer extruder under the film forming conditions described in Table 1, and the layer composed of the mixture A-2 had a thickness of 130 μm and the resin B. -1 is a two-layer film having a thickness of 30 μm and a total thickness of 160 μm, and an adhesive film for protecting a semiconductor wafer is prepared in the same manner as in Example 1 except that an adhesive is applied to the low-density polyethylene resin layer side. Obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 4]
For semiconductor wafer protection in the same manner as in Example 3, except that the thickness of the layer made of the mixture A-2 is 80 μm, the thickness of the layer made of the resin layer B-1 is 80 μm, and the total thickness is 160 μm. An adhesive film was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 5]
For semiconductor wafer protection in the same manner as in Example 3 except that the thickness of the layer made of the mixture A-2 was 45 μm, the thickness of the layer made of the resin layer B-1 was 115 μm, and the total thickness was 160 μm. An adhesive film was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 6]
The α-olefin content of the α-olefin-containing 4-methyl-1-pentene copolymer resin is 45 mol%, the thickness of the layer made of copolymer A-1 is 130 μm, and the thickness of the layer made of resin B-1 is For semiconductor wafer protection in the same manner as in Example 3 except that a double-layer film having a thickness of 30 μm and a total thickness of 160 μm was used and an adhesive was applied to the α-olefin-containing 4-methyl-1-pentene copolymer resin layer side. An adhesive film was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 7]
For semiconductor wafer protection in the same manner as in Example 6 except that the thickness of the layer made of copolymer A-1 was 80 μm, the thickness of the layer made of resin B-1 was 80 μm, and the total thickness was 160 μm. An adhesive film was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 8]
For semiconductor wafer protection as in Example 6, except that the thickness of the layer made of copolymer A-1 was 45 μm, the thickness of the layer made of resin B-1 was 115 μm, and the total thickness was 160 μm. An adhesive film was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Example 9]
A pressure-sensitive adhesive film for protecting a semiconductor wafer was obtained in the same manner as in Example 1 except that the base film was a mixture of A-4 and a single-layer film having a thickness of 160 μm. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. No microcracks (wafer thickness of 15 μm) after grinding were confirmed for the five wafers evaluated. Regarding the damage when picking up the thin wafer after grinding from the heating table, it was possible to pick up the 10 wafers without any damage (breaks, cracks).

[Comparative Example 1]
As base film, ethylene-vinyl acetate copolymer resin with 19% vinyl acetate content (Mitsui / DuPont Polychemical, trade name: Everflex (registered trademark), product number: EV460)), single-screw single-layer extrusion T-die melt extrusion under the film forming conditions listed in Table 1, using a machine, corona-treated on both sides as a 135 μm-thick film, and then a 25 μm-thick polyethylene naphthalate film with one surface corona-treated (Teijin DuPont Films Ltd.) Example, except that the product made by the company, product name: Teonex (registered trademark) and the corona-treated surface was dry laminated and laminated, and the adhesive was applied to the ethylene-vinyl acetate copolymer resin layer side. In the same manner as in No. 1, an adhesive film for protecting a semiconductor wafer was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, burrs were visually recognized in 4 out of 25 wafers in terms of tape cutability. Regarding microcracks after grinding (wafer thickness 15 μm), two of the five wafers evaluated were confirmed. Regarding the damage when picking up the thin wafer after grinding from the heating table, the 10 wafers could be picked up without any damage (cracking, cracking).

[Comparative Example 2]
The semiconductor was the same as Comparative Example 1 except that a 25 μm thick polyethylene terephthalate film (manufactured by Teijin DuPont Films, trade name: Tetron (registered trademark)) was used instead of the 25 μm thick polyethylene naphthalate film. An adhesive film for protecting the wafer was obtained. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, burrs were visually recognized in 2 out of 25 wafers in terms of tape cutability. About the microcrack after grinding (wafer thickness of 15 μm), three out of the five wafers evaluated were confirmed. Regarding the damage when picking up the thin wafer after grinding from the heating table, the 10 wafers could be picked up without any damage (cracking, cracking).

[Comparative Example 3]
As a base film, an ethylene-vinyl acetate copolymer resin (product name: Evaflex (registered trademark), product number: V5401) manufactured by Mitsui DuPont Polychemical Co., Ltd. having a vinyl acetate content of 9% is used as a single-screw single-layer extruder. A pressure-sensitive adhesive film for protecting a semiconductor wafer was obtained in the same manner as in Example 1 except that a film having a thickness of 160 μm was melt-extruded by T-die method under the film forming conditions shown in Table 1. Table 1 shows the physical properties of the obtained base film and adhesive film. As a result of the practical evaluation, as for the tape cut property, no wafer out of 25 wafers in which burrs were visually recognized. The microcracks after grinding (wafer thickness 15 μm) were confirmed for all the five wafers evaluated. About the damage at the time of picking up the thin wafer after grinding from a heating table, all 10 wafers were damaged (crack, crack) because the base material of the adhesive film expressed adhesive force to the heating table.

  ADVANTAGE OF THE INVENTION Even if a semiconductor wafer is thinned by this invention, the semiconductor wafer protection adhesive film which prevents damage to a semiconductor wafer and is excellent in workability | operativity, such as tape cut property, and the semiconductor using the said film A wafer protection method can be provided.

Claims (8)

(1) Melting point [Tm] measured by a differential scanning calorimeter, which is a copolymer of 4-methyl-1-pentene and an α-olefin having 5 to 8 carbon atoms other than 4-methyl-1-pentene A semiconductor wafer comprising a resin layer A comprising a copolymer in the range of 110 to 240 ° C. and a content of the α-olefin having 5 to 8 carbon atoms in the range of 1 to 60 mol% Protective adhesive film The resin layer A is further (2) a polymer of 4-methyl-1-pentene,
Or / and
(3) a polymer of at least one α-olefin selected from α-olefins having 2 to 4 carbon atoms,
The pressure-sensitive adhesive film for protecting a semiconductor wafer according to claim 1, comprising a resin layer A comprising The adhesive film for protecting a semiconductor wafer according to claim 1, wherein the content of the α-olefin having 5 to 8 carbon atoms in the resin layer A is in the range of 5 to 55 mol%. 2. The adhesive film for protecting a semiconductor wafer according to claim 1, comprising a base film layer comprising the resin layer A and a resin layer B having a melting point of 60 ° C. or more. 5. The adhesive film for protecting a semiconductor wafer according to claim 4, wherein in the base film layer, the thickness of the resin layer A is 10% or more of the thickness of the base film layer. 6. The adhesive film for protecting a semiconductor wafer according to claim 5, wherein the resin layer B comprises at least one selected from polyethylene, ethylene-vinyl acetate copolymer, and polypropylene. A method for protecting a semiconductor wafer using the adhesive film for protecting a semiconductor wafer according to claim 1,
A first step of adhering an adhesive film for protecting a semiconductor wafer to a circuit forming surface of a semiconductor wafer via the adhesive layer;
A second step of cutting into a circle along the outer periphery of the wafer to which the film is attached;
A third step of processing and thinning the non-circuit-formed surface of the semiconductor wafer;
A fourth step of adhering the adhesive film for die bonding to the circuit non-forming surface of the semiconductor wafer without peeling off the adhesive film for protecting the semiconductor wafer;
A fifth step of removing the adhesive film for protecting a semiconductor wafer;
Semiconductor wafer protection method including 8. The method for protecting a semiconductor wafer according to claim 7, wherein the second step is a step of grinding, polishing, chemical etching, dry etching, plasma treatment, one of the above steps, or a combination of a plurality of the above steps.